The invention relates to an arrangement or device for the insertion of weft threads into a shed in a weaving machine by means of a jet of fluid and with the use of at least one nozzle, which comprises a thread conveying or entrance duct for guiding the weft thread, a fluid conveying duct for guiding the fluid, and a transporting duct for the joint conveying of a weft thread and a fluid, the transporting duct and the fluid conveying duct being each formed by a leg of a common angled main duct, the flow axes of these two legs forming with one another a substantially obtuse angle, and the thread conveying duct opening into the leg forming the transporting duct in alignment with the said leg.
Two prior art arrangements of this type are already known. In one arrangement the main duct is formed of a bore machined from the solid, and in the other known arrangement it is formed of the bore of a bent-over small tube. It is a common feature of both arrangements that the main duct has throughout its length the same diameter. It has been found in practice that with these prior art arrangements there is a considerable escape of fluid through the thread duct. This fluid escapement is a disadvantage since it slows down the speed of the fluid in the transporting duct and this in its turn means that the length of shot which can be achieved for thread insertion is reduced.
The closest prior art known to applicant in connection with this application is German Pat. No. 865,729 and German Offenlegungschrift No. 1,535,454.